نتایج جستجو برای: dendrochronology
تعداد نتایج: 264 فیلتر نتایج به سال:
SUMMAR Y: The data of Atkinson and Greenwood (1972) on drought damage to trees in 1969.70 in two bush patches in the Manawatu district are reassessed, and an index of drought susceptibility based on their data used to classify species into three categories of susceptibility. The results of this categorisation are compared with independent data on the effects of the 1972-73 drought on the nearby...
This paper introduces a new approach-the Principal Component Gradient Analysis (PCGA)-to detect ecological gradients in time-series populations, i.e. several time-series originating from different individuals of a population. Detection of ecological gradients is of particular importance when dealing with time-series from heterogeneous populations which express differing trends. PCGA makes use o...
Many marine fishes have life history strategies that involve ontogenetic changes in the use of coastal habitats. Such ontogenetic shifts may place these species at particular risk from climate change, because the successive environments they inhabit can differ in the type, frequency and severity of changes related to global warming. We used a dendrochronology approach to examine the physical an...
Dendrochronology (tree-ring science) techniques were applied to otolith growth increments in 3 flatfish species collected from the eastern Bering Sea: northern rock sole Lepidopsetta polyxystra, yellowfin sole Limanda aspera, and Alaska plaice Pleuronectes quadrituberculatus. Within each species, otoliths were visually crossdated to ensure that the correct calendar year was assigned to each gro...
This study examined the influence of climate on cumulative and interannual growth patterns of 18 full-sib families of hybrid poplars (Populus × smithii Boivin) derived from different geographical locations (state counties) of natural stands of aspen parents (trembling aspen (Populus tremuloides Michx.) and bigtooth aspen (Populus grandidentata Michx.)). The hybrids were subsequently planted in ...
The oxygen isotopic composition of plant cellulose is commonly used for the interpretations of climate, ecophysiology and dendrochronology in both modern and palaeoenvironments. Further applications of this analytical tool depends on our in-depth knowledge of the isotopic fractionations associated with the biochemical pathways leading to cellulose. Here, we test two important assumptions regard...
Channels that have been scoured to bedrock by debris flows provide unique opportunities to calculate the rate of sediment and wood accumulation in low-order streams, to understand the temporal succession of channel morphology following disturbance, and to make inferences about processes associated with input and transport of sediment. Dendrochronology was used to estimate the time since the pre...
Annual growth bands of mollusk shells record several types of paleoenvironmental information, including geochemical proxies for water properties and morphological characteristics of growth and mortality. Sclerochronology, the marine counterpart of dendrochronology, offers a way to link individual shells together to form long continuous records of such parameters. It also allows for precise dati...
الگوی حلقههای پهن و باریک را میتوان در میان درختان مختلف یک منطقه مقایسه نمود و سال دقیق تشکیل آن حلقه را درک کرد. این عمل پایه دانش گاهشناسی درختی (Dendrochronology) را میسازد. در این تحقیق با توجه به اهمیت درختان ارس بررسیای بر روی تغییرات حلقههای رویش این گونه در سه رویشگاه لاین(خراسان)، فیروزکوه(تهران) و زنجان به انجام رسید. در هر رویشگاه 15 درخت با مته رویشسنج نمونهبرداری گردید. په...
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